Drier felt



16, 1945- J. R. 1.. SANTOS 2,367,438

DRIER FELT Filed Sept. 17, 1945 2 Sheets-Sheet 1 (/oH/v A. L. SAN-r0 Jan. 16, 1945. J SANTOS 2,367,438

DRIER FELT Filed Sept. 17, 1943 2 Sheets-Sheet 2 Patented Jan. 16, 1945 UNITED STATES PATENT oFFica,

DRIER FELT John R. L. Santos, Baltimore, Md., assignor to William E. Hooper a Sons Company, Baltimore, Md., a corporation of Maryland Application September 17, 1943, Serial No. 502,775 Claims. (Cl. 139-415) increased emphasis in the paper making industry on the maximum production per unit of door space has resulted in a very considerable increase in the speed of the web. This speed gives a decreased period in which the web is ained prior to its arrival at the drying area stack, and this decrease has continued to a point at which the moisture content of the web when it arrives at the drying area, referred to as the stack, is such that the web is in a soft plastic condition, wherefore, manufacturers have experienced increased difliculty because of marking and disfigurement of the finished paper due to irregularities in the surface of the drier felt on which the web is carried and advanced in the drying operation.

To overcome this diiliculty, which is the primary object of the invention, it is necessary to facilitate to the highest degree, and to thus accelerate the discharge of water from the web, in and approaching the drying area, thus relieving the extreme softness of the web, and at the same time to present to the web as smooth a supporting surface as is obtainable without interference with quick discharge of the water through the felt.

A further object of the invention is to produce a felt through which the water and steam can pass freely, permitting the paper web to be dried as easily and quickly as possible, and also to permit the felt to be more easily dried on its return, i. e. on the return or unloaded flight of the felt or belt.

A still further object is to produce a surface on the back of the felt, which facilitates the discharge of water there from and hence the transference of water through the felt, and the drying of the felt itself. This surface also serves a cooling function.

A still further object is to so fabricate the material that the binder warps are as nearly uniform in length as possible, i. e. are uniformly interwoven with the filling, the remaining warps, one or more of each set referred to as stuffer warps being in effect unwoven, and the weft or filling threads being part wholly above and the remainder wholly below the stuifer warps, which are in the center of the fabric.

It is notable that the stuffer warps, while unwoven are closely bound by the weft or filling threads, and considerably indented or kinked, whereby capillarity and absorption are reduced. By the arrangement described, an improved body is imparted to the fabric, whereby its resistance to transverse deformation is, increased, 1. e. the

stuffer warps serve to separate the upper and lower filling threads from each other, maintaining tension therein, and keeping them perpendicular to the warp threads.

It is of particular importance that each set of warp threads consists, solely of one or more stuifer warps, and a number of binder warps, all of which extend directly through the fabric, almost at right angles to its upper surface, and thus assist in draining the water which tends to follow the strands through the felt. Also these binder warps, form the entire exposed surface of the felt, on the side which supports the paper web, which side is exposed to the heated rolls, and these binder warps form an extremely smooth top surface well adapted to support the web in drying. By using asbestos for all the binder warps, the entire exposed surface of the felt on the upper or smooth side which carries the web, and is exposed to the heated rolls, may when desired, be formed entirely of asbestos. While cotton or similar fiber is necessary to give the felt sufficient resistance to tension, and helps to prevent stretching, it is desirable in some installations, to have the exposed portion of the felt, which is adjacent to the heated rolls, of resistive material. Certain of the binder warps are shown as shaded in a manner to indicate asbestos or the like, but this shading is also used to identify these binder warps which may be of cotton or the equivalent.

While the present preferred fabric as shown has three binder warps to one stuffer warp, the proportions may be varied to meet the conditions presented.

Other advantages, features, and details of the invention will be more fully described in connection with the accompanying drawings, in which all of the figures are drawn to an enlarged scale and are mainly diagrammatic in nature. In the accompanying drawings:

Figure 1 is a top plan view of the felt fabric of the invention.

Figure 2 is a section on the line 22 in Figure 1.

Figure 3 is a section on the line 3-3 in Figure 1.

Figure 4 is a top plan view of the fabric as shown in Figures 1, 2, and 3.

Figure 5 is a top plan view, corresponding to Figure 1, showing a slightly modified form.

Figure 6 is a section on the line 6 -6 in Figure 5.

Referring to Figures 1, 2, 3, and 4, it may be noted that these figures show a single set of warps, consisting of four warps indicated by reference characters I, 2, 3, and 4, and also a single warp of a second set.

Figures 1, 2, and 3 also show transverse weft or form shown, includes three binder or surface warps, 2, 3, and 4, and one stuffer warp, l, I and the sets referred to are uniform and are repeated across the full width of the fabric, the number of binder warps in a set being variable.

In the felt which is the, subject of the invention, the stufier or core warps or which I and 5 are examples, are straight and unwoven, part, preferably half of the wefts or filling threads, being above and the remainder of the same being below the stuffer warps. As distinguished from the stuffer or core warps, the binder warps are woven over and under the weft or filling threads. It is an important feature of the invention that each binder or surface warp passes upwardly, spanning two upper wefts or fillings, and then downwardly under one lower filling, as best shown in Figures 2 and 3. In the preferred form, each binder warp, considered as extending from left to right, passes almost directly downwardly from each span, and directly through the fabric, thus passing under the immediately adjacent lower filling.

In this connection, it will be noted, that in the drawings, Figures 1 to 3, the upper fillings bear the even numbers, and are spaced lateraly by the thickness or diameter of the binder warp threads, and. the lower fillings or weft threads are correspondingly spaced, but alternated, relatively to the upper wefts so that each lower filling is directly below the space between two adjacent upper filling, the lower fillings being numbered 1, 9, II, and etc. In the arrangement shown, each binder warp thread as it passes downwardly through a space between two of the upper filling threads, extends about the lower weft which is directly below the space through which the binder-war is passed, so that the tendency of the binder warp at the ends of each span is downwardly almost at right angles, and

directly through the fabric, whereby improved advantages herein rebetween the lines ll, which assist in leading the.

moisture through the felt, the spacing of the wa'ps and wefts as shown being helpful to this en It may be desirable to explain at this point that while the illustration suggests that these binder warps are composed of asbestos, giving a complete asbestos surface, the fact is that the invention is, in its broader scope, not limited to pose instead of asbestos, being included within this disclosure and considered desirable where conditions permit. p

In accordance with the preferred form of the product, the straight or stufler warps l and 5, i. e. all of the stuifer warps, are preferably of cotton or equivalent fiber, having a high degree 'of tensile strength, and the weft or filling threads, the exposure of which to the heat is limited, and considerably less than that of the surface or binder warps are also preferably of cotton or equivalent material, the use of various artiflcial fibers, particularly for core warps and fillings. and some of these for the binder warps. and the use of asbwtos for the weft when desired, being within the scope of the invention.

It is also notable that the filling or weft threads 'are pulled or woven tightly about the stuffer or core warps, thus compressing and indenting the latter at short intervals as at 43, and greatly reducing the capillarity of the fibers, and their tendency to absorb and retain and conduct water. The tightness of the wefts also tends to reduce the capillarity of the weft threads. I

While the illustration, Figures 1 to 5, shows one stufier warp to three surface or binder warps, it is to be understood that other proportions may be employed. An important feature being that all binder warps of each set extend directlythrough the fabric and span the upper filling in the manner described, forming the entire top sunface of the fabric.

It is of importance that with the binder or face warps running directly through the fabric in a direction almost normal to its surface, as described, an open or porous felt is produced, whereby the water or steam may pass through the fabric with comparative ease, thus providing quick draining of the web, and discharge of the water therefrom, also the felt itself is easily and quickly drained on the return flight from the point where it discharges the'paper web to the point where it again picks up the web of wet matted pulp, the porosity and the particular arrangement of the weft and binder or core warps, all contributing to quick discharge of the water and quick drying and radiation of heat.

It is regarded as of importance that the weave as shown has a smooth top surface, composed entirely of the binder or face warps, the other threads not being exposed on this surface. This top surface is extremely smooth as compared to other paper felt fabrics, and is therefore adapted to the purpose in hand. In the modern paper machine, which operates at a very high speed,

the percentage oi! moisture content of the paper where the drier felts are located, though reduced by efiicient discharge incident to the improved felt, is higher than in the 01d type of machine, and the smooth surface described is particularly adapted to support the soft plastic web, and to prevent marking or indention of the web and consequent disfigurement of the paper.

It is further, of importance not only that the stufler warps contribute to the tensile strength and limit stretching, but that the three or any suitable number of face warps or binder warps of each set of warps, all of equal length and tension, and woven in a precisely uniiorm'manner, as described, contribute to the same result, i. e. they reduce the tendency to stretch, and thus give'more economical operation, as the machine this material, the use of cotton for this pur- 7 must, when the felt stretches beyond the spacing of the take-up rolls, be stopped, necessitating the stopping of the entire line of the machines in order that the felt or belt seam may be cut and a new seam sewed. This is an extremely.

expensive operation, considered from the point of view of loss of time of the machine and plant and of labor lost while the machines are idle.

It is also of importance that the relation of the binder warps to the filling and the arrangement of the same as thus described, gives the maximum of resistance to transverse deformation. This resistance to deformation is referred to as body, and is important in insuring even and straight running of the felt through the machine.

While it is frequently of advantage to have the entire top of the web supporting surface of asbestos, byproviding asbestos binding warps or face warps with cotton stuffer or core warps, 'and cotton filling, thus givin by presentation of the asbestos to the heated rolls, the maximum of resistance to heat and acid, it is notable that cotton may be used for the entire fabric or other equivalent fibers may be employed.

Figures and 6 show another form of the fabric in which each set of warps comprises a stuffer or core Warp 2Q or 25 arranged as previously described. Between these core warps are two binder warps, 27 and 28, arranged as described in connection with warps 3 and 4 in Figure 1.

The fillings or filling threads are indicated by reference characters 29, 30, 3!, 32, etc., and are arranged as in the fabric, previously described in connection with Figures 1 to 4.

The purposes and advantages and accomplishment of the invention having been fully described what I claim as new and desire to secure by Letters Patent is:

1. A drier felt fabric consisting of successive uniform sets of threads, each comprising unwoven stuifer warp threads, upper filling threads located wholly on the upper side of the stufferwarps, lower filling threads located wholly on the lower side of the same, and binder warp threads exceeding in number the number of stufier warp threads, all the binding threads being binder warp threads and each of them being uniformly interwoven with the filling threads, and each extending directly through the fabric substantially at right angles to its surface, from the top where it forms successive spans, each overlying a plurality of upper filling threads, to the lower sur face Where each binder Warp is looped beneath a corresponding lower filling thread, the loops in each binder warp being directly beneath a point between the adjacent spans of the same warp, the lower surface of the fabric being composed of the lower filling threads and said loops, the top surface of the fabric being smooth and composed entirely of said spans, a proportion of the binder thread sufficient to form said entire top surface being provided thereat and the remainder of the binder thread performing its binding function and returning it to said top surface substantially as directlyas the pressure of adjacent threads permits.

2. A drier felt fabric consisting of successive uniform sets of threads comprising unwoven stufier warp threads, upper filling threads located wholly on the upper side of the stuifer warps and lower filling threads, located wholly on the lower side of the same, binder warp threads exceeding in number the number of stuffer warp threads, all the binding ,threads being binder warp threads and each of them being uniformly interwoven with the filling threads, and each extending directly through the fabric substantially at right angles to its surface, from the top where itforms successive spans over portions of the upper filling to the lower surface where each binder warp is looped beneath a corresponding lower filling thread, the lower surface of the fab ric being composed of the lower filling threads and said loops, the top surface of the fabric being smooth and composed entirely of said spans, each span consisting of a short portion of binder warp thread extending over a plurality of upper filling threads, and the loops in each binder warp being between the adjacent spans of the same warp, a proportion of the binder thread sufficient to form said entire top surface being provided thereat and the remainder of the binder thread performing its binding function and returning it to said top surface substantially as directly as the pressure of adjacent threads permits.

3. A fabric as per claim 2 in which the binder warps are of asbestos, providing a top, web supporting surface, wholly of asbestos.

4. A drier felt consisting of successive uniform sets of threads, each set comprising unwoven core wap and binder warp in each said set, the latter exceeding in number, the core warp therein, weft threads uniformly distributed, some wholly above, and the remainder, wholly below the core warp, the binder warp being uniformly interwoven with the weft threads, and extending upwardly over two upper weft threads, and then downwardly under one lower weft thread, thus forming successive spans overlying successive pairs of upper weft threads, the latter being spaced apart and the lower weft threads being each located beneath one of said spaces, the binder warps passing downwardly,substantially at right angles to the surface of the felt and through the felt from the end of each span to and about the lower weft thread which underlies the space between the last weft of the pair under one span and the first weft of the pair under the next span, and then upwardly to and over the next pair of upper weft threads, and repeating throughout the felt, the core warp threads being tightly compressed, and indented by and between the weft threads, reducing the absorption and capillarity thereof, the binder warp threads being the sole binding threads in said drying felt.

5. A drier felt consisting of uniform sets of threads comprising unwoven core warp threads and binder warp threads in each set exceeding in number the core warp therein,,weft threads uniformly distributed, some wholly above, and the remainder wholly below the core warp threads, the binder warp threads of each set being uniformly interwoven with the weft threads, and extending consecutively over a plurality of upper weft threads, and then under one lower weft thread, thus forming successive spans overlying successive pairs of upper weft threads, the latter being spaced apart, and the lower weft threads being located beneath one of said spaces, and the binder warp threads passing downwardly in a direction, substantially normal to the surface of the felt and through the same from the end of each span to and about the lower weft thread, which underlies the space between the last weft under one span and the first weft under the next span, and then upwardly to the next span and repeating through the felt, the said spans composing the entire top surface of the felt and forming a supporting surface for-the paper web, the binder warp threads being the sole bindin, and weft threads imiformly distributed, some wholly above, and the remainder wholly below the core warp threads, the binder warps being uniformly interwoven with the weft threads, and extending consecutively over two upper weft threads, and then under one lower weft thread, thus forming successive spans overlying successive pairs of upper weft threads, the latter being spaced apart and the lower weft threads being threads, and then under one lower weft thread,

thus forming successive spans, overlying successive pairs of upper weft threads, the latter being spaced apart and the lower weft threads being each located beneath one of said spaces, and the binder warp threads passing downwardly in a direction, substantially normal to the surface of the felt and through the same from the end of each span to and about the lower weft thread which underlies the space between the last weft under one span and the first weft under the next span, and then upwardly to the next span and repeating through the felt, the said spans composing the entire top surface of the felt and forming a supporting surface for the paper web, said binder warps being of asbestos, whereby said top surface is composed entirely Of asbestos fibers, the binder warp threads being the sole binding threads in said drying felt.

7. A drier felt consisting of uniform sets of threads, comprising unwoven straight core warp threads and binder warp threads in each set exceeding in number the core warp threads therelocated each beneath one of said spaces, the binder warp threads passing downwardly substantially at right angles to the surface of the felt and through the same from the end of each span to and about the lower side of the lower weft,

which underlies the space between the last upper weft of one pair and the first upper weft of the next pair, and then upwardly in approximately, the same direction to and over the next pair of upper weft threads, the bottom surface of the fabric being composed of the lower wefts and the portion of binder warp threads, which pass around the lower sides of said lower weft threads at each crossing of the same, the spans forming a smooth top surface to support the web, the binder warp threads being the sole binding threads in said drying felt.

8. A drier felt as per claim 6, in which there are two binder warp threads to each core warp thread. 1

9. A drier felt as per claim 7 in which there are two binderwarp threads to each core warp thread.

10. A drier felt as per claim 4, in which there are two binder warp threads to each core warp thread.

JOHN R. L. SANTOS. 

